A disputed election in Afghanistan has thrown Western strategy into turmoil, forcing an intense public debate while the Taliban gains ground. We'll talk live with Dr. Abdullah Abdullah in Kabul, President Karzai's chief rival.

The West also faces a host of other challenges, from Somalia to Sudan to Iran. We'll have an exclusive report on Iran's political refugees and where they're headed.

And what is the best way to deal with Iran's nuclear program? For all of that, we'll speak with Britain's ambassador to the United Nations, Sir John Sawers, who has firsthand experience with all these issues and who is also about to take on a new job.

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UNIDENTIFIED FEMALE: I admire your luck, Mister...

SEAN CONNERY, ACTOR: Bond. James Bond.

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AMANPOUR: Sir James Bond is the world's image of British intelligence, living the high life in between perilous assignments. But today, we have the real thing, in fact, the next head of MI6, British intelligence, a man who will be walking into a tangle of much less glamorous, but very serious global challenges.

Sir John Sawers, welcome. Thanks for coming to the program.

SIR JOHN SAWERS, INCOMING MI6 CHIEF: Christiane, thank you very much.

AMANPOUR: So shall we just dive right in and...

SAWERS: Of course, please.

AMANPOUR: ... you're going to tell me all about the secrets?

SAWERS: I think not, but I'm very happy to talk about some of the issues that I've been dealing with here in the United Nations.

AMANPOUR: Let me ask you, first, obviously, as you take on this new job -- not to be a spoiler, but there has been some criticism, some in Britain, including a former sea chief (ph), have said that your experience is much more political than in the intelligence service. You were there briefly, you came out, and now you're going to go back in.

Can you handle all that's necessary in a non-political, non-partisan way?

SAWERS: I think so. I've been greatly honored to be asked to do this job. It's running one of the institutions which is greatly respected in my country. We've got some very serious national security issues to -- to pursue. I'm a professional civil servant. I'll support the government of the day. That's where I'm -- that's what my profession is. And I'm very much looking forward to doing that over the coming months and years.

AMANPOUR: What would you say are the most important challenges you just mentioned? What would you say are number one at the top of that?

SAWERS: Well, number one, I think is the threat that we face to our own security from terrorism around the world and, in particular, the threat that's posed by Al Qaida and its -- its associates.

AMANPOUR: That is still a live threat, right?

SAWERS: We believe it is. There hasn't been -- there hasn't been a major attack in a Western capital for some time, but we know, from Al Qaida activities in places like Algeria, in Indonesia and elsewhere, that there is still a serious threat that the associates of Al Qaida can pose to us.

We are working with the government of Pakistan, and we're working very extensively in Afghanistan, of course, to try to close down the space available for Al Qaida and their -- their sympathizers. And, you know, it's -- it's a long and protracted process, but we believe we are making progress in that goal.

AMANPOUR: Does it worry you that, with the Taliban gaining momentum, as the United States has now said, Secretary Gates said that to -- to myself in -- in an interview we did earlier this week, does it worry you that if, eventually, Afghanistan might fall to the Taliban, that would provide new space for Al Qaida?

SAWERS: Well, yes, that is obviously a concern. And there's a long record of Taliban providing space for Al Qaida. The Taliban are under some pressure. They're under pressure in Pakistan, which is where they've had a major base, and we very much welcome and support the actions that the Pakistani authorities have been taking to close down the space available to them in the border areas there.

And, yes, there have been some successes, if you like, by -- by Taliban in -- in Afghanistan. They had terrible bombing against the Indian embassy today. But at the same time, they're also under pressure there. The -- the level of Western forces in places like Helmand and Kandahar is higher than it was before, and we are -- we are bringing more Afghan civilians into areas where they are safer and they're not under the sway and under the control of the Taliban and other extremist groups, and that's progress.

AMANPOUR: So the reason I ask you is because there seems to be a debate right now in the United States at least about the -- about whether - - if Afghanistan fell and the Taliban should come back, whether that would provide space for Al Qaida. I want to just play you what Secretary Gates said about that.

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ROBERT GATES, SECRETARY OF DEFENSE: The reality is, failure in Afghanistan would be a huge setback for the United States. Taliban and Al Qaida, as far as they're concerned, defeated one superpower. For them to be seen to defeat a second, I think, would have catastrophic consequences in terms of energizing the extremist movement, Al Qaida recruitment, operations, fundraising, and so on. I think it would be a huge setback for the United States.

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AMANPOUR: That, of course, was Secretary Gates speaking to John King on "State of the Union." However, do you agree with that?

SAWERS: Well, we certainly don't disagree about the dangers that the Taliban poses to -- to international interests, because they have this track record of working with Al Qaida. Now, if there are elements of the Taliban that want to sign up to the Afghan Constitution, which are -- who are willing to pay a peaceful -- play a peaceful part in the politics in Afghanistan, then they're welcome to do so.

AMANPOUR: How realistic do you think that is?

SAWERS: Well, I don't think the Taliban is a monolithic organization. I think there is a -- a central leadership of the Taliban, but many of the tribes and the militias that are fighting in the Taliban's name are doing so because they're -- they're paid more or because they think the Taliban in the end are going to win out. If we can change that calculation, then they're more likely to move over.

AMANPOUR: I guess the reason I'm asking is because there is this debate going on in Washington and, as you know, probably in your -- in your own capital, as well, and President Obama has spoken to Prime Minister Brown apparently today about the whole way forward, more troops, counterinsurgency, or a scale back, pure counterterrorism effort.

In a recent speech just this week, President Obama -- we can show you again on this Wordle thing we have. It's a word cloud which emphasizes words that are used. In a speech on terrorism, President Obama did not mention the word "Afghanistan." We'll show you. It'll come up in a second.

In fact, it's on the wall. If we look over there, there's not a single mention of the word Afghanistan. Are we to believe that Afghanistan, no matter what happens, is no longer a threat of terrorism and Al Qaida?

SAWERS: No. I don't want to interpret what President Obama has said. He -- he -- he will speak for himself, and he's leading at the moment a very intensive review of American policy about Afghanistan and how we best -- how we best deal with the terrorist threat.

Now, a similar debate is going on in other Western capitals. It's certainly going on in London, about what exactly is the best way forward and how best do we resource the international effort in Afghanistan?

The United States will take the lead. The United States is playing the biggest role, and other Western countries, Britain included, will play an active support to that -- to that effort.

Now, I think we're all agreed that no one's trying to create a perfect society in Afghanistan. We are there in order to prevent Afghanistan being a base for terrorists. The debate is how best you achieve that, and what is the right mix between...

AMANPOUR: Would you do it by pulling back or by doubling up the fight?

SAWERS: Well, and I think those are extreme possibilities. And actually, the real debate is somewhere much closer to the middle. It's, to what extent do you -- do you try and increase your presence and -- and -- and strengthen your presence on the ground in Afghanistan? Or do you stand back and allow the Afghans to take the lead? I think there is...

AMANPOUR: But they're not up yet.

SAWERS: Well, exactly. And that's the main point, is that we have to intensify our efforts to ensure that there is effective Afghan security forces that can -- that can take the strain of the -- of the -- of -- of managing security threats inside Afghanistan.

AMANPOUR: Is Britain prepared to put in even more troops? It already has the second-largest number after the United States.

SAWERS: We have -- we have 9,000 troops in Afghanistan. Decisions on that are taken by the prime minister after receiving military advice. So these decisions will be taken at the right time. And we've sustained a large military presence in Afghanistan. We believe that others could -- could -- could do more. And we will wait until the United States has made a strategic decision before we take any more decisions on this.

AMANPOUR: So it's wait and see how this debate goes?

SAWERS: Yes.

AMANPOUR: Let's switch over to Iran. What do you understand happened in Geneva this last week? Your negotiators were there, as well. Has Iran agreed -- yes, to the inspections of Qom at the end of this month, or the 25th or so, but what about the notion of shipping out its low-enriched uranium? Is that a deal that you understand that has been made?

SAWERS: We believe that there was a constructive start to these negotiations, and both these issues were discussed, and we believe progress was made on both of them. The international atomic energy authority has a date to visit this new secret -- hitherto secret facility at Qom, which raises real concerns for us.

This facility, it seems to be more than a pilot facility and nothing like big enough for an industrial facility. So what was its purpose? Why was it deep inside a military base? So we believe there's progress on that particular point.

On the question of whether the existing low-enriched uranium can be taken out of -- of Iran and rendered harmless by turning it into fuel rods, that is -- that would be a step forward. Now, we believe that there was discussion -- there was discussion of this issue in Geneva. The details will need to be tied down.

It doesn't solve the fundamental problem, which is that we still do not have confidence as to why Iran is trying to master the most sensitive bits of the nuclear fuel cycle in the first place. So they need to demonstrate to us that their program is entirely for peaceful purposes, and we are far from satisfied on that point yet.

AMANPOUR: Would -- is the international community or Britain, the United States, the West, inching towards accepting a certain level of Iranian enrichment, particularly with a shipping out of low-enriched uranium?

SAWERS: Well, we've never ruled that out. What we've sought is a more -- is a -- a suspension of all their -- their nuclear enrichment facilities and their nuclear enrichment activities. And that suspension should continue until such time as we are satisfied and confident that their program is purely peaceful.

We'd never ask them for a complete disbandment of all their enrichment in perpetuity. But they do have to prove to us and to international community generally that their program is purely for peaceful purposes. And they haven't done that.

AMANPOUR: Do you think that these talks -- the United States are spinning them as positive. Quite frankly, there's a big difference of -- of reaction these days. The U.S. is being much more positive towards what's going on between the West and Iran, whereas the Europeans -- Britain, France, Germany -- are being more hard-line. For instance, we've seen all of your country say that you have evidence that there -- that they have started a weaponization program.

SAWERS: Well, I think the jury is still out on this question. None of us are sure what is happening in Iran on their nuclear program, and that's why we need to have much more effective cooperation between Iran and the IAEA and much greater transparency. We are certainly not satisfied at this stage that Iran's program is purely peaceful. And I don't think the United States is, either.

Now, whether there are fine differences in the analysis of what information we have is -- is -- is a secondary issue. The fact is that it is far from clear -- and none of us are certain about this, and we will need to be certain.

AMANPOUR: And you -- many of you talk about incentives and disincentives, carrots and sticks, and the sticks are obviously -- well, there's, I suppose, military option, which most people say won't be effective, and there's the sanctions option, which you have worked on in the United Nations. I mean, what do you say to those who basically are looking and seeing that sanctions have literally done nothing, have not affected the behavior of the Iranian government on their nuclear program?

SAWERS: Well, first of all, we are committed to finding a political and diplomatic solution to this problem. Nobody wants there to be a military confrontation over it. So we are determined to do everything we possibly can to find a political solution to it.

Now, we've agreed that we -- Britain, France, Germany, United States, Russia, and China -- that there should be a two-track approach, that we should seek to engage Iran so that the Iranians respond and cooperate with us and, if they don't do so, that we will impose sanctions against them.

We've had three rounds of sanctions through the United Nations. And European countries and the United States have sanctions that go beyond that. We're prepared to go further down that road if there's not Iranian cooperation. But if there is Iranian cooperation and the Iranians do what the Security Council is requiring of them to do, which is suspend their most sensitive nuclear activities, then we're happy to suspend the sanctions, as well.

So it's a clear path for Iran. They can cooperate and they can gain a great deal by doing so, or they can refuse to do so, they can persist with their -- with their obscurity and their -- their secrecy and their -- their nuclear program without meeting their obligations to the international atomic energy authority, in which case we will press for further sanctions.

AMANPOUR: And what do you think they'll achieve, those sanctions?

SAWERS: Well, I think we've seen in the aftermath of the Iranian elections that there are some quite serious differences within the Iranian regime, not just between the -- the opponents of the Islamic regime, but actually within the leadership of the existing regime.

And I think there's a debate going on. What price should they pay for their opposition to international norms and standards? Or what -- what could they benefit if they actually achieve the more normal relationship between Iran and the West, in particular? And that debate is going on.

AMANPOUR: We have time for one more question, and it's way over the other side of the world. You spend most of your time, I think, as U.N. ambassador at the Security Council, at the U.N., and yet you did go to the Congo for a special trip.

SAWERS: Yes.

AMANPOUR: What -- what -- that was about sexual violence.

SAWERS: Well, I've been to the Congo each year for the last three years. And the problem of sexual violence as a -- as a tool of war has grown even worse in -- in -- in Africa in recent years. And in the east of Congo, it is what the Congolese foreign minister himself described as the worst crimes against humanity anywhere in the world in the 21st century.

So I believe that we've actually achieved a higher profile for the -- the fight against systematic sexual violence. I think a number of -- of campaigners in the West -- people like Eve Ensler, people like the NGO Women for Women -- have done a great deal to highlight the problem. And the United Nations and the secretary general and the U.N. peacekeeping forces now have the prevention of sexual violence very high on the priority list.

It's not been achieved yet, but the fact that we persuaded the Congolese authorities to arrest and remove from office five of their own military officers involved in sexual violence is an important step forward in this fight.

AMANPOUR: Thank you, Sir John Sawers. We could go on and on, and hopefully we'll get a chance in the future.

SAWERS: Thank you. Thank you very much, Christiane.

AMANPOUR: Thanks a lot for coming in.

SAWERS: Thank you.

AMANPOUR: And we'll have more on Afghanistan next. Presidential candidate, former foreign minister Dr. Abdullah Abdullah will join us from Kabul.

Welcome to our program. Could I just ask you about the theme that we've been discussing, and that is terrorism? As the United States has this review, can I ask your opinion of what you think? Should the Taliban not be defeated, will that return Al Qaida?

ABDULLAH ABDULLAH, AFGHAN PRESIDENTIAL CANDIDATE: Yes, Afghanistan will return back to the late '90s, where it was the bases for Al Qaida or the global capital for Al Qaida. I have no doubt in my mind. Should this happen, this will be the consequence.

AMANPOUR: And what do you think, then, as the U.S. and Britain and the others are debating, do you believe there should be more troops sent to Afghanistan at this time to beat back the Taliban?

ABDULLAH: I think it's essential that the call by General McChrystal is responded positively, because that's what's needed on the ground, but more troops will not be a substitute for the failure of a national government. So hopefully, through the process, we have legitimate government so it could partner with the United States in helping not only defeating terrorism, but stabilizing Afghanistan and putting the process, democratic process on track.

AMANPOUR: There's obviously been huge controversy after your elections. We've all followed it. There's presumably going to be some announcement next week, a final announcement. What will happen if President Karzai is announced as the winner even after the fraudulent ballots are removed? Would you be able to work with such a government, even though I know you -- you ran on a -- on a platform of change for Afghanistan?

ABDULLAH: No, I think with taking the fraudulent vote out or excluding it, there's no possibility or eventuality of President Karzai winning in the first round. There is no doubt. Even the limited audit and recount process, which has started a few days ago and completed today, it shows the initial results, that he will be below 50 percent, and let alone the 751 serious complaints, which on its own will change the outcome of the elections.

So if you're asking about a cover-up, if you're asking about a whitewash or something as such, should that happen, then will I be able to work with such a government? No, of course, absolutely no.

AMANPOUR: And what do you think, in terms of as the West goes forward, how will they be able to work in this environment, presumably with new troops or not?

ABDULLAH: I think the environment has deteriorated, unfortunately, security-wise, governance, corruption, and so on and so forth. And this recent fraud, in massive state-engineered fraud, engineered by the incumbent, that made it difficult for everybody.

But as a whole, I think legitimate government, a government which has the mandate from its own people, will be able to -- to -- to deliver to its own people on its own part in partnering with the international community. I think that's the solution in order to -- to put things on track and look towards a better future for Afghanistan...

AMANPOUR: Doctor...

ABDULLAH: ... to stabilize Afghanistan and democratic Afghanistan.

AMANPOUR: Dr. Abdullah, thank you so much. And we will talk to you again.

And we will back right after a break.

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AMANPOUR: And now for our "P.S.," or our post-script. Tonight, we're focusing on the fallout from the crackdown on pro-democracy protestors in Iran. Hundreds of opposition activists and ordinary demonstrators are now fleeing their homeland across the mountain passes to Turkey. We have that story from CNN's Ivan Watson.

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IVAN WATSON, CNN CORRESPONDENT (voice-over): The border town of Van in eastern Turkey, it's the first stop on what some call the underground railroad for people escaping from neighboring Iran.

To get here, some Iranians make a dangerous, illegal journey on foot over the mountains, with the help of smugglers. When they arrive, they're stranded in a foreign country, facing an uncertain future, perhaps never to see their family again.

Meet one of the newest arrivals.

ARASH, IRANIAN REFUGEE: I love my country, and I love Iran, but nowadays I must be not in Iran. I must run away.

WATSON: His name is Arash, and he's part of a fresh wave of Iranian opposition activists now running for their lives. This close to Iran, he says it's still too dangerous for us to show his face.

ARASH: Because they want to arrest me to go to prison.

WATSON: Until last June, Arash worked for the so-called Green Wave election campaign of presidential candidate Mir Hossein Mousavi. The trouble started when Mahmoud Ahmadinejad was declared winner of the election, amid widespread allegations of fraud.

Street protests erupted, prompting a government crackdown and the arrest of thousands of opposition activists like Arash. About 100 people have since been paraded on TV in mass trials, accused of plotting to overthrow the government. Some of those who were detained have alleged torture and even rape, charges the government has denied.

Arash says he went into hiding and then fled on foot to Turkey.

ARASH: What they -- the government do that with the elections is coup d'etat, coup d'etat.

WATSON: Here at the United Nations' High Commissioner for Refugees Office in Turkey, officials say the number of Iranian asylum-seekers has nearly doubled to around 200 a month since the crackdown began last summer. Among the new refugees, this former official from the campaign of another opposition presidential candidate, Mehdi Karroubi. He also fears being identified.

"I fled with my family to Turkey," he says, "because I'm afraid of being arrested and tortured."

Lily Mazahery is an American immigration lawyer helping Arash and other new Iranian dissidents get asylum in the West.

LILY MAZAHERY, IMMIGRATION LAWYER: These guys are saying, "We were working with the campaigns legally. We were part of the system. And now we've been ostracized."

WATSON: Arash now spends his days in exile, often watching Iranian soccer games with other Iranian refugees, and dreaming of one day going home.

ARASH: I love my country, and I want to come back to Iran soon, as soon as possible.

WATSON: Ivan Watson, CNN, Van in eastern Turkey.

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AMANPOUR: Newsweek journalist and filmmaker Maziar Bahari is still arrested and imprisoned without charges. His wife is expecting their first baby, and his boss is asking for his immediate release on humanitarian grounds. Our conversation continues online on our Web site, cnn.com/amanpour. We have a special feature there on Afghanistan.

That's it for now. Thank you for joining us. We will be back with the next big story tomorrow.